Electronic Device

ABSTRACT

An electronic device includes a display screen, a camera, and a first display buffer. The display screen includes a first display area and a second display area, and a material of a display screen corresponding to the second display area is a transparent material. The camera is disposed below the display screen and opposite to a second display area. The first display buffer is configured to store a display signal of the first display area and a display signal of the second display area, and send the display signal of the first display area to the first display area. The first display buffer is further configured to determine, based on whether the camera is started, whether to send the display signal of the second display area to the second display area.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of International Application No.PCT/CN2021/090276, filed on Apr. 27, 2021, which claims priority toChinese Patent Application No. 202010376098.6, filed on May 7, 2020. Thedisclosures of the aforementioned applications are hereby incorporatedby reference in their entireties.

TECHNICAL FIELD

This application relates to the field of electronic devices, and morespecifically, to an electronic device.

BACKGROUND

With popularization of intelligent electronic devices, users have ahigher requirement on a screen-to-body ratio of electronic devices.

In an electronic device with a relatively high screen-to-body ratio, asmall hole that matches a size of a front-facing camera is disposed on adisplay screen of the electronic device, and then the front-facingcamera is placed in the small hole, so that the user can take a selfie.There is no display unit at the hole in the display screen of theelectronic device, that is, no content is displayed at a position of thefront-facing camera, thereby affecting an overall display effect of thescreen, and causing poor user experience.

SUMMARY

This application provides an electronic device. In the electronicdevice, a material of an area that is of a display screen and that isopposite to a front-facing camera may be set to a transparent material.When the front-facing camera is not started, the area of the displayscreen corresponding to the front-facing camera may display content, andthe content matches content displayed in another area of the entireelectronic device other than the area that is of the display screen andthat is opposite to the front-facing camera, so that an overall displayeffect of the screen of the electronic device is not affected, and userexperience is improved.

According to a first aspect, this application provides an electronicdevice, including: a display screen, where the display screen includes afirst display area and a second display area, and a material of adisplay screen corresponding to the second display area is a transparentmaterial; a camera, where the camera is disposed below the displayscreen and opposite to the second display area; and a first displaybuffer, where the first display buffer is configured to store a displaysignal of the first display area and a display signal of the seconddisplay area, and send the display signal of the first display area tothe first display area; and the first display buffer is furtherconfigured to determine, based on whether the camera is started, whetherto send the display signal of the second display area to the seconddisplay area.

The foregoing camera refers to a front-facing camera, and thefront-facing camera may be used by a user to photograph a foreground orthe user to take a selfie.

The foregoing electronic device may be a mobile phone.

The electronic device includes the display screen, the camera disposedbelow the display screen, and the first display buffer. The displayscreen includes the first display area and the second display area, andthe material of the display screen corresponding to the second displayarea is a transparent material, and the second display area is disposedopposite to the camera. The first display buffer stores the displaysignal of the first display area and the display signal of the seconddisplay area. The first display buffer may send the display signal ofthe first display area to the first display area, and the first displaybuffer determines, based on whether the camera is started, whether tosend the display signal of the second display area to the second displayarea, so that the overall display effect of the electronic device is notaffected, and user experience is improved.

With reference to the first aspect, in a possible implementation, thefirst display buffer is further specifically configured to: when thecamera is not started, send the display signal of the second displayarea to the second display area, and control matching between thedisplay signal sent to the first display area and the display signalsent to the second display area; or when the camera is started, preventthe display signal of the second display area from being sent to thesecond display area.

Matching between the display signal sent to the second display area andthe display signal sent to the first display area may be understood asfollows: On the display screen of the electronic device, contentdisplayed in the second display area and content displayed in the firstdisplay area may form a complete image.

When the camera of the electronic device is not started, the firstdisplay buffer sends the display signal of the second display area tothe second display area, and controls matching between the displaysignal sent to the first display area and the display signal sent to thesecond display area, so that when the camera of the electronic device isnot started, an overall display effect of the electronic device is notaffected, and user experience is improved. When the camera is started,the display signal of the second display area is prevented from beingsent to the second display area, so that when the camera of theelectronic device is started, the user's use of the camera of theelectronic device is satisfied, and user experience is improved.

With reference to the first aspect, in a possible implementation, thefirst display buffer includes a sub buffer section, where the sub buffersection is used to store the display signal of the second display area,the sub buffer section includes a flag, and the flag is used to indicatewhether the camera is started.

A sub buffer section is disposed in the first display buffer, and thesub buffer section is used to store the display signal of the seconddisplay area. The sub buffer section includes a flag, and the flagindicates whether the camera is started. Therefore, the first displaybuffer may determine, based on the flag, whether the camera is started,so as to determine whether to send the display signal buffered in thesecond display area to the second display area, so as to completedisplaying on the second display area. Therefore, the overall displayeffect of the electronic device is not affected, and user experience isimproved.

With reference to the first aspect, in a possible implementation, when avalue of the flag is true, the camera is not started; or when the valueof the flag is false, the camera is started.

With reference to the first aspect, in a possible implementation, theelectronic device further includes a second display buffer, where thesecond display buffer is configured to read a display signal that is ofthe second display area and that is stored in the first display buffer,and the second display buffer is further configured to: when the camerais not started, send the display signal of the second display area tothe second display area; or when the camera is started, prevent thedisplay signal of the second display area from being sent to the seconddisplay area.

The second display buffer is disposed in the electronic device, and thesecond display buffer may read the display signal that is of the seconddisplay area and that is stored in the first display buffer; or when thecamera is not started, the second display buffer sends the displaysignal of the second display area to the second display area, so thatwhen the camera of the electronic device is not started, the displaysignal is displayed in the second display area. Therefore, the overalldisplay effect of the electronic device, and user experience isimproved. When the camera is started, the display signal of the seconddisplay area is prevented from being sent to the second display bufferin the second display area, so that the user's use of the camera of theelectronic device is satisfied, and user experience is improved.

Optionally, the second display buffer determines, in two manners,whether the camera of the electronic device is started. In a firstmanner, the first display buffer may detect whether the camera of theelectronic device is started, and send an instruction to the seconddisplay buffer, where the instruction is used to indicate whether thecamera of the electronic device is started. The second display bufferdetermines, based on the foregoing instruction, whether to send thedisplay signal of the transparent area to the transparent area. In asecond manner, the second display buffer may detect whether the cameraof the electronic device is started, and determine, based on a result ofdetecting whether the camera of the electronic device is started,whether to send the display signal of the transparent area to thetransparent area.

With reference to the first aspect, in a possible implementation, whenthe camera is not started, the second display buffer is furtherconfigured to drop a frame, so that the display signal sent to the firstdisplay area matches the display signal sent to the second display area,and the second display buffer is further configured to determine aquantity D of dropped frames based on the following formula:

D=(B+C−A)×f

where f is a frame rate; A is a time at which the first buffer sends thedisplay signal of the first display area to the first display area; B isa time at which the second buffer reads the display signal of the seconddisplay area from the first buffer; and C is a time at which the secondbuffer sends the display signal of the second display area to the seconddisplay area.

When the camera is not started, the second display buffer may perform aframe dropping operation based on relationships between the time atwhich the first buffer sends the display signal of the first displayarea to the first display area, the time at which the second bufferreads the display signal of the second display area from the firstbuffer, and the time C at which the second buffer sends the displaysignal of the second display area to the second display area, and theframe rate, so that the display signal sent to the first display areamatches the display signal sent to the second display area, and theoverall display effect of the electronic device is not affected.

With reference to the first aspect, in a possible implementation, whenthe camera is started, the camera captures an image by using the seconddisplay area.

With reference to the first aspect, in a possible implementation, thedisplay screen includes a first display screen and a second displayscreen, where the first display screen is corresponding to the firstdisplay area, and the second display screen is corresponding to thesecond display area.

With reference to the first aspect, in a possible implementation,display brightness of the second display area is a times displaybrightness of the first display area, where a is greater than or equalto 1; and a may be obtained by collecting statistics about historicalbrightness data used by the user for the electronic device.

Specifically, because a camera is disposed opposite to the seconddisplay area, and a color of the camera is relatively dark, there is amismatch between the display brightness of the second display area andthe display brightness of the first display area. Therefore, the displaybrightness of the second display area is a times the display brightnessof the first display area, and a is greater than or equal to 1, so thatthe display brightness of the first display area can achieve a samedisplay effect as the second display area, thereby improving userexperience.

With reference to the first aspect, in a possible implementation, amaterial of the display screen corresponding to the first display areais a transparent material.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic structural diagram of an electronic deviceaccording to an embodiment of this application;

FIG. 2 is a schematic structural diagram of an electronic device;

FIG. 3(a)-FIG. 3(d) are schematic diagrams of a group of graphical userinterfaces (GUIs) of an electronic device;

FIG. 4(a)-FIG. 4(b) are schematic diagrams of another group of GUIs ofan electronic device;

FIG. 5(a)-FIG. 5(d) are schematic diagrams of a group of GUIs accordingto an embodiment of this application;

FIG. 6(a)-FIG. 6(b) are schematic diagrams of another group of GUIsaccording to an embodiment of this application;

FIG. 7 is a schematic structural diagram of a display screen of anelectronic device according to an embodiment of this application;

FIG. 8 is a schematic diagram of pixel-level coordinates according to anembodiment of this application;

FIG. 9 is a schematic structural diagram of an electronic deviceaccording to an embodiment of this application;

FIG. 10 is a schematic structural diagram of a display buffer accordingto an embodiment of this application; and

FIG. 11 is a schematic structural diagram of another display bufferaccording to an embodiment of this application.

DESCRIPTION OF EMBODIMENTS

The following describes technical solutions in this application withreference to accompanying drawings.

An electronic device in an embodiment of this application may include ahandheld device, an in-vehicle device, a wearable device, a computingdevice, or another processing device connected to a wireless modem; mayalso include a subscriber unit, a cellular phone (cellular phone), asmart phone (smart phone), a wireless data card, a personal digitalassistant (personal digital assistant, PDA) computer, a tablet computer,a modem (modem), a handset (handset), a laptop computer (laptopcomputer), a machine type communication (machine type communication,MTC) terminal, a point of sales (point of sales, POS), an in-vehiclecomputer, a station (station, ST) in a wireless local area network(wireless local area network, WLAN); or may be a cellular phone, acordless phone, a session initiation protocol (session initiationprotocol, SIP) phone, a wireless local loop (wireless local loop, WLL)station, a terminal device in a next-generation communications system(such as a 5G network), a terminal device in a public land mobilenetwork (public land mobile network, PLMN), or another electronic devicewith a camera. For example, the communications apparatus may be a mobilephone, a tablet computer, or an electronic product with a camera.

The wearable device may also be referred to as a wearable smart device,and is a general term for daily wearable devices that are smartlydesigned and developed by using wearable technologies, such as glasses,gloves, watches, apparels, and shoes. A wearable device is a portabledevice that can be worn directly on the body or integrated into theclothing or accessories of a user. The wearable device is not merely ahardware device, it can implement a powerful function based on softwaresupport, and data interaction, and cloud interaction. Generalizedwearable smart devices include large-sized smart devices that canimplement some functions without relying on a smartphone, such assmartwatches or smart glasses, and also include smart devices that focuson a particular application function and need to work with anotherdevice such as a smartphone, such as smart bands and smart jewelry thatare used for sign monitoring.

The following uses an example in which the electronic device is a mobilephone for detailed description.

FIG. 1 is a schematic structural diagram of an electronic device 100according to an embodiment of this application. The electronic device100 may include a processor 110, an antenna 1, an antenna 2, a mobilecommunications module 120, a wireless communications module 130, amemory 140, a charging management module 150, a power management module151, a battery 152, and a display screen 160.

It may be understood that a structure shown in an embodiment of thisapplication does not constitute a specific limitation on the electronicdevice 100. In some other embodiments of this application, theelectronic device 100 may include more or fewer components than thoseshown in the figure, or combine some components, or split somecomponents, or have different component arrangements. The componentsshown may be implemented by hardware, software, or a combination ofsoftware and hardware.

The processor 110 may include one or more processing units. For example,the processor 110 may include an application processor (applicationprocessor, AP), a modem processor, a graphics processing unit (graphicsprocessing unit, GPU), an image signal processor (image signalprocessor, ISP), a controller, a memory, a video codec, a digital signalprocessor (digital signal processor, DSP), a baseband processor, and/ora neural-network processing unit (neural-network processing unit, NPU).Different processing units may be independent devices, or may beintegrated into one or more processors.

The controller may be a neural center and a command center of theelectronic device 100. The controller may generate an operation controlsignal based on an instruction operation code and a time sequencesignal, so as to control retrieval and execution of the instruction.

A memory may also be disposed on the processor 110 to store aninstruction and data. In some embodiments, the memory in the processor110 is a cache memory. The memory may store an instruction or data thatis just used or used cyclically by the processor 110. If the processor110 needs to use the instruction or data again, the instruction or datamay be directly invoked from the memory. Repeated access is avoided, anda waiting time of the processor 110 is reduced, thereby improving systemefficiency.

In some embodiments, the processor 110 may include one or moreinterfaces. The interface may be an inter-integrated circuit(inter-integrated circuit, I2C) interface, an inter-integrated circuitsound (inter-integrated circuit sound, I2S) interface, a pulse codemodulation (pulse code modulation, PCM) interface, a universalasynchronous receiver/transmitter (universal asynchronousreceiver/transmitter, UART) interface, a mobile industry processorinterface (mobile industry processor interface, MIPI) interface, ageneral-purpose input/output (general-purpose input/output, GPIO)interface, a subscriber identity module (subscriber identity module,SIM) interface, a universal serial bus (universal serial bus, USB)interface, and/or the like.

The antenna 1 and the antenna 2 are configured to transmit and receiveelectromagnetic wave signals. Each antenna in the electronic device 100may be configured to cover a single or a plurality of communicationsbands. Different antennas may be multiplexed to improve antennautilization. For example, the antenna 1 may be multiplexed into adiversity antenna of a wireless local area network. In some otherembodiments, the antenna may be used in combination with a tuningswitch.

The electronic device 100 may include a communications module,configured to communicate with an external device. For example, thecommunications module may include a mobile communications module 120 anda wireless communications module 130.

The mobile communications module 120 may provide a wirelesscommunication solution that is applied to the electronic device 100,including 2G/3G/4G/5G. The mobile communications module 120 may includeat least one filter, a switch, a power amplifier, a low noise amplifier(low noise amplifier, LNA), and the like. The mobile communicationsmodule 120 may receive an electromagnetic wave from the antenna 1,perform processing such as filtering and amplification on the receivedelectromagnetic wave, and send the electromagnetic wave to the modemprocessor for demodulation. The mobile communications module 120 mayfurther amplify a signal modulated by the modem processor, and convertthe signal into an electromagnetic wave and radiate the electromagneticwave by using the antenna 1. In some embodiments, at least some of thefunctional modules of the mobile communications module 120 may bedisposed in the processor 110. In some embodiments, at least some of thefunctional modules of the mobile communications module 120 may bedisposed in a same device as at least some of the modules of theprocessor 110.

The wireless communications module 130 may provide a wirelesscommunication solution that is applied to the electronic device 100,including wireless local area network (wireless local area network,WLAN) (such as a wireless fidelity (wireless fidelity, Wi-Fi) network),Bluetooth (Bluetooth, BT), global navigation satellite system (globalnavigation satellite system, GNSS), frequency modulation (frequencymodulation, FM), near field communication (near field communication,NFC), infrared (infrared, IR), and the like. The wireless communicationsmodule 130 may be one or more components that integrate at least onecommunication processing module. The wireless communications module 130receives an electromagnetic wave by using the antenna 2, modulates andfilters the electromagnetic wave signal, and sends the processed signalto the processor 110. The wireless communications module 130 may furtherreceive a to-be-sent signal from the processor 110, perform frequencymodulation and amplification on the signal, and convert the signal intoan electromagnetic wave and radiate the electromagnetic wave by usingthe antenna 2.

In some embodiments, the antenna 1 of the electronic device 100 iscoupled to the mobile communications module 120, and the antenna 2 iscoupled to the wireless communications module 130, so that theelectronic device 100 can communicate with a network and another deviceby using a wireless communications technology. The wirelesscommunications technology may include a global system for mobilecommunications (global system for mobile communications, GSM), a generalpacket radio service (general packet radio service, GPRS), code divisionmultiple access (code division multiple access, CDMA), wideband codedivision multiple access (wideband code division multiple access,WCDMA), time-division code division multiple access (time-division codedivision multiple access, TD-SCDMA), long term evolution (long termevolution, LTE), BT, GNSS, WLAN, NFC, FM, an IR technology, and thelike. The GNSS may include a global positioning system (globalpositioning system, GPS), a global navigation satellite system (globalnavigation satellite system, GLONASS), a Beidou navigation satellitesystem (Beidou navigation satellite system, BDS), a quasi-zenithsatellite system (quasi-zenith satellite system, QZSS), and/or asatellite based augmentation system (satellite based augmentationsystem, SBAS).

The memory 140 may be configured to store computer executable programcode, where the executable program code includes an instruction. Theprocessor 110 executes various function applications and data processingof the electronic device 100 by running an instruction stored in thememory 140. The memory 140 may include a program storage area and a datastorage area. The program storage area may store an operating system, anapplication program required by at least one function (such as a soundplay function or an image play function), or the like. The data storagearea may store data (such as audio data or a phone book) created duringuse of the electronic device 100. In addition, the memory 140 mayinclude a high-speed random access memory, and may also include anon-volatile memory, such as at least one magnetic disk storage device,a flash memory device, or a universal flash storage (universal flashstorage, UFS).

The charging management module 150 is configured to receive a charginginput from a charger. The charger may be a wireless charger, or may be awired charger. In some wired charging embodiments, the chargingmanagement module 150 may receive a charging input of a wired charger byusing a USB interface. In some wireless charging embodiments, thecharging management module 150 may receive a wireless charging input byusing a wireless charging coil of the electronic device 100. In additionto charging the battery 152, the charging management module 150 mayfurther supply power to the electronic device 100 by using the powermanagement module 151.

The power management module 151 is configured to connect the battery152, the charging management module 150, and the processor 110. Thepower management module 151 receives an input of the battery 152 and/oran input of the charging management module 150, and supplies power tothe processor 110, the memory 140, the display 160, the mobilecommunications module 120, the wireless communications module 130, andthe like. The power management module 151 may be further configured tomonitor parameters such as a battery capacity, a quantity of batterycycles, and a battery health state (leakage or impedance). In some otherembodiments, the power management module 151 may alternatively bedisposed in the processor 110. In some other embodiments, the powermanagement module 151 and the charging management module 150 mayalternatively be disposed in a same device.

The electronic device 100 implements a display function by using theGPU, the display screen 160, the application processor, and the like.The GPU is a microprocessor for image processing, and is connected tothe display screen 160 and the application processor. The GPU isconfigured to perform mathematical and geometric calculations and isconfigured to render graphics. The processor 110 may include one or moreGPUs that execute a program instruction to generate or change displayinformation.

The display screen 160 is configured to display an image, a video, andthe like. The display screen 160 includes a display panel. The displaypanel may be a liquid crystal display (liquid crystal display, LCD), anorganic light emitting diode (organic light-emitting diode, OLED), anactive matrix organic light emitting diode (active-matrix organic lightemitting diode, AMOLED), a flex light emitting diode (flexlight-emitting diode, FLED), a Miniled, a MicroLed, a Micro-oLed,quantum dot light emitting diodes (quantum dot light emitting diodes,QLED), or the like. In some embodiments, the electronic device 100 mayinclude one or N display screens 160, where N is a positive integergreater than 1.

Currently, to meet users' requirements on electronic devices,screen-to-body ratios of more and more electronic devices areincreasingly high. For example, FIG. 2 is a schematic diagram of anelectronic device with a hole-dug screen. The hole-dug screen means thata hole is dug in the display screen for placing a front-facing camera.In the display screen 500 shown in FIG. 7, a hole 161 is disposed in anarea 163 of the display screen 500. The hole 161 penetrates the displayscreen 500 in a thickness direction of the display screen. A size of thehole 161 matches a size of a front-facing camera 162, and thefront-facing camera 162 is disposed in the hole 161, so as to meet auser's requirement on use of the front-facing camera 162 of theelectronic device.

For example, FIG. 3(a)-FIG. 3(d) are schematic diagrams of a group ofgraphical user interfaces (graphical user interface, GUI) of anelectronic device with a hole-dug screen. Referring to FIG. 3(a), theGUI is a desktop of the electronic device. The desktop of the electronicdevice includes three desktop pages, and each desktop page includesicons of one or more application programs. The current desktop of theelectronic device displays a second desktop page, and the desktop pageincludes a “Weather” icon, a “Theme” icon, a “Music” icon, a “Video”icon, an “Album” icon, a “Card package” icon, a “Settings” icon, and a“Camera” icon. In this case, because no corresponding display unit isdisposed in the area 163 corresponding to the front-facing camera 162 inthe electronic device, the front-facing camera 162 of the electronicdevice can be seen in the area 163 that passes through the electronicdevice. When the electronic device detects that the user taps the“Album” icon, the GUI of the electronic device is a display interfaceshown in FIG. 3(b). When the electronic device detects that the usertaps the “Camera” icon, the GUI of the electronic device is a displayinterface shown in FIG. 3(c). When the electronic device detects thatthe user taps the first picture, the GUI of the electronic device is adisplay interface shown in FIG. 3(d). In this case, a display unit isnot disposed at a position of the area 163 of the electronic device, andtherefore, the area 163 does not display any content. The user can stillsee the front-facing camera 162, and the user cannot see the picturecontent that is shielded by the camera 162 in the picture, therebyaffecting an overall display effect of the electronic device.

For another example, FIG. 4(a)-FIG. 4(b) are schematic diagrams ofanother group of GUIs of an electronic device with a hole-dug screen.Referring to FIG. 4(a), the GUI is a desktop of the electronic device.The desktop of the electronic device includes four desktop pages, andeach desktop page includes icons of one or more application programs.The current desktop of the electronic device displays a second desktoppage, and the desktop page includes a “Weather” icon, a “Theme” icon, a“Music” icon, a “Video” icon, an “Album” icon, a “Card package” icon, a“Settings” icon, and a “Camera” icon. In this case, the front-facingcamera 162 of the electronic device can be seen in the area 163 thatpasses through the electronic device. After the electronic devicedetects that the user clicks the “Camera” icon, the GUI of theelectronic device is a display interface shown in FIG. 4(b). In thiscase, because no display unit is disposed at a position of the area 163of the electronic device, the area 163 does not display any content, andthe user can still see the front-facing camera 162.

For example, FIG. 5(a)-FIG. 5(d) are schematic diagrams of a group ofGUIs of an electronic device according to an embodiment of thisapplication. Referring to FIG. 5(a), the GUI is a desktop of theelectronic device. The desktop of the electronic device includes fivedesktop pages, and each desktop page includes icons of one or moreapplication programs. The current desktop of the electronic devicedisplays a second desktop page, and the desktop page includes a“Weather” icon, a “Theme” icon, a “Music” icon, a “Video” icon, an“Album” icon, a “Card package” icon, a “Settings” icon, and a “Camera”icon. In this case, a material of the display screen in the area 163corresponding to the front-facing camera 162 in the electronic device isa transparent material, and a corresponding display unit is disposed.Therefore, when the electronic device detects that the front-facingcamera 163 is not started, corresponding content is displayed in thearea 163, and the front-facing camera 162 of the electronic devicecannot be seen in the area 163 of the electronic device. When theelectronic device detects that the user taps the “Album” icon, the GUIof the electronic device is shown in FIG. 5(b). When the electronicdevice detects that the user taps the “Camera” icon, the GUI of theelectronic device is a display interface shown in FIG. 5(c). When theelectronic device detects that the user taps the first picture, the GUIof the electronic device is shown in FIG. 5(d). In this case, the usercan see the entire picture.

For another example, FIG. 6(a)-FIG. 6(b) are schematic diagrams ofanother group of GUIs of an electronic device according to an embodimentof this application. Referring to FIG. 6(a), the GUI is a desktop of theelectronic device. The desktop of the electronic device includes fourdesktop pages, and each desktop page includes icons of one or moreapplication programs. The current desktop of the electronic devicedisplays a second desktop page, and the desktop page includes a“Weather” icon, a “Theme” icon, a “Music” icon, a “Video” icon, an“Album” icon, a “Card package” icon, a “Settings” icon, and a “Camera”icon. In this case, a material of the display screen in the area 163corresponding to the front-facing camera 162 in the electronic device isa transparent material, and a corresponding display unit is disposed.Therefore, when the electronic device detects that the front-facingcamera 163 is not started, corresponding content is displayed in thearea 163, and the front-facing camera 162 of the electronic devicecannot be seen in the area 163 of the electronic device. After theelectronic device detects that the user taps the “Camera” icon, the GUIof the electronic device is a display interface shown in FIG. 6(b). Inthis case, because the electronic device detects that the front-facingcamera 162 is started, the display unit at the position of the area 163does not display content, and the user may see the front-facing camera162 by using the area 163, that is, the user may take a selfie.

When the front-facing camera of the electronic device is not started,the area 163 of the electronic device displays corresponding content(which forms complete content with the content displayed in anon-transparent area 164), so that an overall display effect of theelectronic device is not affected. When the front-facing camera 162 ofthe electronic device is started, the area 163 of the electronic devicedoes not display content, so that the front-facing camera 162 of theelectronic device captures an image by using the area 163, therebyimproving user experience.

To facilitate understanding of this embodiment of this application, thefollowing descriptions are provided before the embodiment of thisapplication is described.

First, in all the accompanying drawings in an embodiment of thisapplication, directions of the x-axis, the y-axis, and the z-axis areperpendicular to each other. The direction of the z-axis may beunderstood as a thickness direction of the electronic device, and thedirection of the z-axis is a direction from a rear case of theelectronic device to a screen of the electronic device. The direction ofthe x-axis may be understood as a length direction of the electronicdevice. The direction of the y-axis may be understood as a widthdirection of the electronic device.

Second, in an embodiment of this application, “upper” or “lower” refersto a positional relationship in the direction of the z-axis, “upper”refers to a positive direction along the z-axis, and “lower” refers to anegative direction along the z-axis.

Third, in the embodiments shown in the following, “the first”, “thesecond”, and various numerical numbers are merely described forconvenient differentiation, and are not used to limit the scope of theembodiment of this application. For example, the numerical numbers areused to distinguish between different display buffers.

Fourth, in an embodiment of this application, a mobile phone is used asan example of an electronic device for description.

Fifth, in an embodiment of this application, the “front-facing camera”is used by a user to photograph a foreground or take a selfie.

FIG. 7 is a schematic structural diagram of an organic light-emittingdiode (organic light-emitting diode, OLED) display screen 500 of theelectronic device 100. The OLED display screen 500 includes a glasssubstrate 510, an anode 520, a hole transport layer 530, an organiclight emitting layer 540, an electron transport layer 550, and a metalcathode 560. A material of the substrate 510 may be transparent plastic,glass, or metal foil, and the substrate 510 is configured to support theentire organic light-emitting diode display screen 500. The anode 520 istransparent, so that light emitted inside the device can be observedfrom the outside. The anode 520 is connected to a positive electrode ofan external drive voltage (2-10V direct current) of the device. Holes inthe anode 520 move to the organic light emitting layer 540 in the deviceunder the driving of the external drive voltage. When current flows inthe electronic device 100, the anode 520 may eliminate electrons. Thehole transport layer 530 includes organic material molecules used totransmit “holes” from the anode 520 to the organic light emitting layer540. The organic light emitting layer 540 includes organic materialmolecules. The organic light emitting layer 540 is configured to emitlight. The organic light emitting layer 540 includes a red lightemitting layer 541, a green light emitting layer 542, and a blue lightemitting layer 543. The electron transport layer 550 includes organicmaterial molecules, and these molecules transmit “electrons” from themetal cathode 560. The metal cathode 560 may be transparent, or may beopaque. When current flows in the electronic device 100, the metalcathode 560 injects electrons into the circuit.

Under the action of an external electric field, electrons aretransmitted from the metal cathode 560 to the electron transport layer550, and the electron transport layer 550 transmits the electrons fromthe metal cathode 560 to the organic light emitting layer 540. Likewise,holes are transmitted from the anode 520 to the hole transport layer530, and the hole transport layer 530 transmits the holes from the anode520 to the organic light emitting layer 540, so that the electrons andholes are recombined in the organic light emitting layer 540 to emitphotons. The photons are emitted from the substrate 510 to implementluminescence of the OLED 500.

Based on the OLED shown in FIG. 7, an embodiment of this applicationprovides two display screen structures of the electronic device 100. Ina first display screen structure, based on the OLED shown in FIG. 7, anarea that is on the OLED and that is corresponding to the front-facingcamera 162 is filled with a transparent material. For example, as shownin FIG. 7, an area opposite to the front-facing camera 162 is 163, andthe front-facing camera 162 is disposed on a side of the metal cathode560 of the display screen, where a projection size of the front-facingcamera 162 on the xy plane is the same as or similar to a projectionsize of a transparent material-filled area on the xy plane. In a seconddisplay screen structure, based on FIG. 7, the electronic transportlayer 550, the organic light emitting layer 540, and the hole transportlayer 530 in the OLED structure are all made of transparent materials.

1. Display Screen Structures

The following separately describes the foregoing two display screenstructures. For ease of description, in an embodiment of thisapplication, the first display screen structure is denoted as a displayscreen structure 1, and the second display screen structure is denotedas a display screen structure 2.

(1) Description of a Manufacturing Process of the Display ScreenStructure 1

In the manufacturing process of the display screen structure 1, aconventional OLED manufacturing process is followed, and after aconventional OLED manufacturing process, the following manufacturingprocess is further performed: marking a coordinate matrix of a pixellevel of an area that is on the OLED and that is corresponding to thefront-facing camera 162. For example, as shown in FIG. 8, pixel-levelcoordinate matrix marking is performed at the position of the area 161corresponding to the front-facing camera 162 on the display screen ofthe electronic device 100, and a transparent material is filled when theposition of the area 161 corresponding to the front-facing camera 162(that is, a marked pixel-level coordinate matrix) is detected.

Optionally, after the foregoing display screen structure 1 ismanufactured, the foregoing display screen may include a first displayscreen and a second display screen. The first display screen iscorresponding to an area other than an area corresponding to theforegoing front-facing camera 162, the second display screen iscorresponding to the area corresponding to the front-facing camera 162,and a material of the second display screen is a transparent material.

(2) Description of a Manufacturing Process of the Display ScreenStructure 2

In the manufacturing process, the display screen structure 2 ismanufactured in a sequence of a substrate, an anode, a hole electronlayer, an organic light emitting layer, an electron transport layer, anda metal cathode. Before the screen structure 2 is manufactured,corresponding position coordinates of three layers (a hole electronlayer, an organic light emitting layer, and an electron transport layer)of transparent material may be marked. For example, as described in FIG.7, position coordinates of the hole electron layer 530, the organiclight emitting layer 540, and the electronic transport layer 550 areseparately marked. For example, the coordinate of the hole electronlayer 530 along the z-axis is z1, the coordinate of the organic lightemitting layer 540 along the z-axis is z2, and the coordinate of theelectronic transport layer 550 along the z-axis is z3. When it isdetected that the z-axis coordinate of the current to-be-manufacturedlayer is z1, the to-be-manufactured layer is made of a transparentmaterial; when it is detected that the z-axis coordinate of the currentto-be-manufactured layer is z2, the to-be-manufactured layer is made ofa transparent material; and when it is detected that the z-axiscoordinate of the current to-be-manufactured layer is z3, theto-be-manufactured layer is made of a transparent material.

Optionally, after the foregoing display screen structure 2 ismanufactured, a material of the foregoing display screen is atransparent material.

For example, FIG. 9 is a schematic diagram of an electronic device 100according to an embodiment of this application. Regardless of whetherthe electronic device 100 uses the foregoing display screen structure 1or the foregoing display screen structure 2, when the electronic device100 is in an off-screen state or the front-facing camera 162 of theelectronic device 100 is started, a position corresponding to thefront-facing camera 162 may present a color of the front-facing cameraor present a color similar to the color of the camera.

2. Drive Circuit of a Display Signal in a Display Area of a DisplayScreen

For ease of description, the position area of the display screencorresponding to the front-facing camera 162 is denoted as a transparentarea, and the area of the display screen other than the position areacorresponding to the front-facing camera 162 is denoted as anon-transparent area. As shown in FIG. 9, the transparent area is 163,and the non-transparent area is 164.

The electronic device 100 provided in an embodiment of this applicationmay further include a first display buffer, where the first displaybuffer stores a display signal of the transparent area 163 and a displaysignal of the non-transparent area 164. The first display buffer maysend the display signal of the non-transparent area 164 to thenon-transparent area 164, and the first display buffer may furtherdetermine, based on whether the camera is started, whether to send thedisplay signal of the transparent area 163 to the transparent area 163.Specifically, when the front-facing camera 162 of the electronic device100 is not started, the first display buffer may send the display signalof the transparent area 163 to the transparent area 163, and controlmatching between the display signal sent to the transparent area 163 andthe display signal sent to the non-transparent area 164; or when thefront-facing camera 162 of the electronic device 100 is started, thefirst display buffer may prevent the display signal of the transparentarea 163 from being sent to the transparent area 163.

When the foregoing camera 162 is started, the camera 162 may capture animage by using the transparent area 163.

Matching between a display signal sent to the transparent area 163 and adisplay signal sent to the non-transparent area 164 may be understoodas: On the display screen of the electronic device 100, contentdisplayed in the transparent area 163 and content displayed in thenon-transparent area 164 may form a complete image.

The following describes in detail, in a manner 1 and a manner 2, drivingof a display signal in a display area of a display screen. Regardless ofwhether the display signal of the display area of the display screen isdriven in either of the following two manners, the first display buffersends the display signal of the non-transparent area 164 to thenon-transparent area 164.

Manner 1: The transparent area 163 and the non-transparent area 164 useone set of drive circuits.

As shown in FIG. 10, a sub buffer (sub buffer) section is separately setin the first display buffer (display buffer), the sub buffer section isused to store a display signal of the transparent area 163, and a flag(flag) is set for the sub buffer section, and the flag is used toindicate whether the front-facing camera 162 is started. For example,when the front-facing camera 162 of the electronic device 100 is notstarted, flag=true or flag=0, and in this case, the transparent area 163displays content, and content displayed in the transparent area 163 andthe non-transparent area 164 is a complete picture. When thefront-facing camera 162 of the electronic device 100 is started,flag=false or flag=1, and in this case, the transparent area 163 doesnot display content.

Specifically, the first display buffer detects whether the front-facingcamera 162 of the electronic device 100 is started. When a value of theflag in the sub buffer section is true or 0, that is, the front-facingcamera 162 of the electronic device 100 is not started, the displaybuffer sends a display signal that is of the transparent area 163 andthat is stored in the sub buffer section to the transparent area 163. Inthis case, the first display buffer also sends a display signal of thenon-transparent area 164 to the non-transparent area 164, and contentdisplayed in the transparent area 163 and content displayed in thenon-transparent area 164 may form a complete image. In this case, astate of the transparent area 163 may be referred to as a displaycontent mode. When the value of the flag in the sub buffer section isfalse or 1, that is, the front-facing camera 162 of the electronicdevice 100 is started, the first display buffer sends the display signalof the non-transparent area 164 stored in the display buffer to thenon-transparent area 164, and the first display buffer prevents thedisplay signal of the transparent area 163 stored in the sub buffersection in the display buffer from being sent to the transparent area163. In this case, the first display buffer sends the display signal ofthe non-transparent area 164 to the non-transparent area 164, and thetransparent area 163 does not display any content. The transparent area163 presents a color of the camera 163, or the transparent area 163presents a color similar to the color of the camera 163. In this case,the transparent area 163 may be referred to as a non-display contentmode. By setting the flag to different values, it is determined whetherthe front-facing camera 162 is started, so that the first display buffercan control the transparent area 163 to implement switching between thedisplay content mode and the non-display content mode.

Manner 2: The transparent area 163 and the non-transparent area 164 usetwo sets of drive circuits.

In addition to the foregoing first display buffer, a second displaybuffer may be further disposed in the electronic device 100, and thesecond display buffer may read a display signal stored in a transparentarea 163 in the first display buffer. When the front-facing camera 162of the electronic device 100 is not started, the second display buffermay further send, to the transparent area 163, a display signal of thetransparent area 163 read from the first display buffer; or when thefront-facing camera 162 of the electronic device 100 is started, thesecond display buffer prevents a display signal of the transparent area163 read from the first display buffer from being sent to thetransparent area 163.

Optionally, the second display buffer may determine, in two manners,whether the front-facing camera 162 of the electronic device 100 isstarted. In a first manner, the first display buffer may detect whetherthe front-facing camera 162 of the electronic device 100 is started, andsend an instruction to the second display buffer, where the instructionis used to indicate whether the front-facing camera 162 of theelectronic device 100 is started. The second display buffer determines,based on the foregoing instruction, whether to send the display signalof the transparent area 163 to the transparent area 163. In a secondmanner, the second display buffer may detect whether the front-facingcamera 162 of the electronic device 100 is started, and determine, basedon a result of detecting whether the front-facing camera 162 of theelectronic device 100 is started, whether to send the display signal ofthe transparent area 163 to the transparent area 163.

The transparent area 163 and the non-transparent area 164 useindependent drives and circuits. When the front-facing camera 162 of theelectronic device 100 is not started, the second display buffer needs tosend, to the transparent area 163, a display signal that is read fromthe first display buffer and that is presented in the transparent area163, so as to present content in the transparent area 163. In this case,the first display buffer also sends a display signal of thenon-transparent area 164 to the non-transparent area 164. When thefront-facing camera 162 of the electronic device 100 is started, thesecond display buffer prevents the display signal that is read from thefirst display buffer and that is presented in the transparent area 163from being sent to the transparent area 163. In this case, the firstdisplay buffer also sends the display signal of the non-transparent area164 to the non-transparent area 164, so that the user can use thefront-facing camera 162 of the electronic device 100.

3. Matching between brightness of the transparent area 163 andbrightness of the non-transparent area 164

The foregoing electronic device 100 is of a display screen structure 1.For the non-transparent area 164, if the transparent area 163 needs toachieve a same display effect, the brightness of the transparent area163 and the brightness of the non-transparent area 164 need to bematched.

Specifically, a front-facing camera 163 is disposed opposite to thetransparent area 163 of the electronic device 100, and a color of thefront-facing camera 163 is relatively dark, so that brightness presentedin the transparent area 163 does not match brightness presented in thenon-transparent area 164. Therefore, the transparent area 163 requiresgreater display brightness, that is, the transparent area 163 requiresbrightness conversion. For example, the brightness conversioncoefficient may be a, and a is greater than or equal to 1. When thebrightness of the non-transparent area 164 is b, an actual displaybrightness of the transparent area is a product of a and b.

The brightness conversion coefficient a may be obtained by collectingstatistics about historical brightness data used by the user for theelectronic device 100.

Specifically, the transparent area 163 may capture brightness of thenon-transparent area 164 in real time, and use a product of thebrightness of the non-transparent area 164 and a as the brightness ofthe transparent area 163.

4. Matching between a display signal of the transparent area 163 and adisplay signal of the non-transparent area 164

When the front-facing camera 162 of the electronic device 100 is notstarted, a display signal sent to the transparent area 163 and a displaysignal sent to the non-transparent area 164 need to be matched.

In the foregoing manner 1, because the transparent area 163 and thenon-transparent area 164 use one set of drives and circuits, there is nomismatch between the display signal of the transparent area 163 and thedisplay signal of the non-transparent area 164.

In the foregoing manner 2, because the transparent area 163 and thenon-transparent area 164 use independent drives and circuits, it takestime for the display buffer corresponding to the transparent area 163 toread, from the display buffer corresponding to the non-transparent area164, the display signal presented in the transparent area 163, and thetransparent area 163 sends the read display signal of the transparentarea 163 to the transparent area 163. Therefore, there may be a case inwhich the display signal of the transparent area 163 and the displaysignal of the non-transparent area 164 do not match in the foregoingmanner 2.

For example, as shown in FIG. 11, the first display buffer is thedisplay buffer corresponding to the non-transparent area 164, and thesecond display buffer is the display buffer corresponding to thetransparent area 163. A sending time of the first display buffer is A,and a sending time of the display buffer 1 may be understood as a timeat which the first display buffer sends the display signal to thenon-transparent area 164. The second display buffer reads, from thefirst display buffer, the display signal presented in the transparentarea 163 at a time B, and the second display buffer then sends, to thetransparent area 163, the display signal read from the first displaybuffer that is presented in the transparent area 163 at a time C. IfA=B+C, the display signal of the transparent area 163 and the displaysignal of the non-transparent area 164 match. If A<B+C, the displaysignal in the transparent area 163 and the display signal in thenon-transparent area 164 do not match. In this case, the second displaybuffer needs to perform a frame dropping operation on the display signalin the transparent area 163. In this case, a quantity D of frames thatneed to be dropped by the second display buffer may be represented byusing the following formula:

D=(B+C−A)×f

where f is a frame rate, for example, the frame rate f is 60frames/second.

The foregoing B, C, A, and f are determined by hardware of theelectronic device.

For example, if the sending time A of the first display buffer is threeseconds, and the sending time B+C of the second display buffer is fourseconds, content displayed in the transparent area 163 is one secondlater than content displayed in the non-transparent area 164, that is,content displayed in the transparent area 163 in the fourth second iscontent that should be displayed in the transparent area 163 in thethird second. Therefore, the second display buffer needs to drop Dframes, so that content displayed in the transparent area 163 in thefourth second is content that should be displayed in the transparentarea 163 in the fourth second, thereby implementing synchronizationbetween the display content of the transparent area 163 and the displaycontent of the non-transparent area 164.

For example, if the foregoing f is 60 frames/second and B+C−A=1 second,the second display buffer needs to drop 60 frames, that is, the secondbuffer needs to drop frames that are read from the first display bufferwithin 1 second. If the second display buffer reads frames within 30seconds from the first display buffer, that is, the second displaybuffer reads 1800 frames, in this case, the second display buffer needsto drop the frames read within the first second of the 30 seconds, thatis, the second display buffer drops frames 1-60 and sends frames 61-1800to the second display area, so that on the electronic device, contentdisplayed in the first display area of the display screen and contentdisplayed in the second display area of the display screen match at the30th second.

For example, as shown in FIG. 9, regardless of whether the electronicdevice 100 uses the foregoing display screen structure 1 or theforegoing display screen structure 2, when the front-facing camera 162of the electronic device 100 is not started, the transparent area 163and the non-transparent area 164 present corresponding content, andtherefore, a boundary 167 between the transparent area 163 and thenon-transparent area 164 is not presented. When the front-facing camera162 of the electronic device 100 is started, because the transparentarea 163 presents a color of the front-facing camera 162 or presents acolor similar to the color of the front-facing camera 162, thenon-transparent area 164 presents corresponding content, the boundary167 between the transparent area 163 and the non-transparent area 164 ispresented. For example, a shape of the boundary between the transparentarea 163 and the non-transparent area 164 may be circular, oval, orpolygonal.

Optionally, the content displayed in the transparent area 163 may notmatch the content displayed in the non-transparent area. For example,the content displayed in the transparent area 163 has nothing to do withthe content displayed in the non-transparent area 164. In someembodiments, the transparent area 163 may display fixed content. Forexample, the fixed content may be time or a logo (logo).

The foregoing descriptions are merely specific implementations of thisapplication, but are not intended to limit the protection scope of thisapplication. Any variation or replacement readily figured out by aperson skilled in the art within the technical scope disclosed in thisapplication shall fall within the protection scope of this application.Therefore, the protection scope of this application shall be subject tothe protection scope of the claims.

What is claimed is:
 1. An electronic device, comprising: a displayscreen, wherein the display screen comprises a first display area and asecond display area, and wherein a material of a display screencorresponding to the second display area is a transparent material; acamera, wherein the camera is disposed below the display screen andopposite to the second display area; and a first display buffer, whereinthe first display buffer is configured to: store a display signal of thefirst display area and a display signal of the second display area; sendthe display signal of the first display area to the first display area;determine whether the camera is started; when the camera is not started,send the display signal of the second display area to the second displayarea, and control matching between the display signal sent to the firstdisplay area and the display signal sent to the second display area; andwhen the camera is started, prevent the display signal of the seconddisplay area from being sent to the second display area.
 2. Theelectronic device of claim 1, wherein the first display buffer comprisesa sub buffer section configured to store the display signal of thesecond display area, wherein the sub buffer section comprises a flag,and wherein the flag indicates whether the camera is started.
 3. Theelectronic device of claim 2, wherein a value of the flag is true whenthe camera is not started, and wherein the value of the flag is falsewhen the camera is started.
 4. The electronic device of claim 1, furthercomprising a second display buffer configured to: read the displaysignal that is of the second display area and that is stored in thefirst display buffer; when the camera is not started, send the displaysignal of the second display area to the second display area; and whenthe camera is started, prevent the display signal of the second displayarea from being sent to the second display area.
 5. The electronicdevice of claim 4, wherein when the camera is not started, the seconddisplay buffer is further configured to drop a frame, so that thedisplay signal sent to the first display area matches the display signalsent to the second display area, and wherein the second display bufferis further configured to determine a quantity D of dropped frames basedon a formula given by:D=(B+C−A)×f wherein f is a frame rate, A is a time at which the firstbuffer sends the display signal of the first display area to the firstdisplay area, B is a time at which the second buffer reads the displaysignal of the second display area from the first buffer, and C is a timeat which the second buffer sends the display signal of the seconddisplay area to the second display area.
 6. The electronic device ofclaim 5, wherein when the camera is started, the camera captures animage using the second display area.
 7. The electronic device of claim6, wherein the display screen comprises a first display screen and asecond display screen, wherein the first display screen corresponds tothe first display area, and wherein the second display screencorresponds to the second display area.
 8. The electronic device ofclaim 1, wherein a display brightness of the second display area is amultiplied by a display brightness of the first display area, andwherein a is greater than or equal to
 1. 9. The electronic device ofclaim 8, wherein a material of the display screen corresponding to thefirst display area is a transparent material.
 10. The electronic deviceof claim 8, wherein a value of a is based on historical brightness datastatistics of the electronic device.
 11. A method, comprising: storing,in a first display buffer, a display signal of a first display area anda display signal of a second display area, wherein a display screencomprises the first display area and the second display area, andwherein a camera is disposed below the display screen and opposite tothe second display area; sending the display signal of the first displayarea to the first display area; determining whether the camera isstarted; sending the display signal of the second display area to thesecond display area, and controlling matching between the display signalsent to the first display area and the display signal sent to the seconddisplay area when the camera is not started; and preventing the displaysignal of the second display area from being sent to the second displayarea when the camera is started.
 12. The method of claim 11, wherein thefirst display buffer comprises a sub buffer section configured to storethe display signal of the second display area, wherein the sub buffersection comprises a flag, and wherein the flag indicates whether thecamera is started.
 13. The method of claim 12, wherein a value of theflag is true when the camera is not started, and wherein the value ofthe flag is false when the camera is started.
 14. The method of claim11, further comprising: a second display buffer configured to: reading,by a second display buffer, the display signal that is of the seconddisplay area and that is stored in the first display buffer; sending, bythe second display buffer, the display signal of the second display areato the second display area when the camera is not started; andpreventing the display signal of the second display area from being sentto the second display area when the camera is started.
 15. The method ofclaim 14, further comprising: dropping, by the second display buffer, aframe when the camera is not started, so that the display signal sent tothe first display area matches the display signal sent to the seconddisplay area; and determining, by the second display buffer, a quantityD of dropped frames based on a formula given by:D=(B+C−A)×f wherein f is a frame rate, A is a time at which the firstbuffer sends the display signal of the first display area to the firstdisplay area, B is a time at which the second buffer reads the displaysignal of the second display area from the first buffer, and C is a timeat which the second buffer sends the display signal of the seconddisplay area to the second display area.
 16. The method of claim 15,wherein the camera being started comprises capturing, by the camera, animage using the second display area.
 17. The method of claim 16, whereinthe display screen comprises a first display screen and a second displayscreen, wherein the first display screen corresponds to the firstdisplay area, and wherein the second display screen corresponds to thesecond display area.
 18. The method of claim 11, wherein a displaybrightness of the second display area is a multiplied by a displaybrightness of the first display area, and wherein a is greater than orequal to
 1. 19. The method of claim 18, wherein a material of thedisplay screen corresponding to the first display area is a transparentmaterial.
 20. An electronic device, comprising: a display screen,wherein the display screen comprises a first display area and a seconddisplay area, and wherein a material of a display screen correspondingto the second display area is a transparent material; a camera, whereinthe camera is disposed below the display screen and opposite to thesecond display area; and a first display buffer; and a second displaybuffer, wherein the first display buffer is configured to: store adisplay signal of the first display area and a display signal of thesecond display area; send the display signal of the first display areato the first display area; determine whether the camera is started; sendan instruction to the second display buffer that indicates whether thecamera is started; and when the camera is not started, control matchingbetween the display signal sent to the first display area and thedisplay signal sent to the second display area; and wherein the seconddisplay buffer is configured to: read the display signal that is of thesecond display area and that is stored in the first display buffer; whenthe instruction indicates that the camera is not started, send thedisplay signal of the second display area to the second display area;and when the instruction indicates that the camera is started, preventthe display signal of the second display area from being sent to thesecond display area.